The Study Of Air-borne Intelligent Distributed Controlling Network Data Acquisition System Based On LonWorks

The fieldbus technique has many characteristics, including high reliability, good stability, strong anti-jamming ability, rapid corresponding velocity, and low-price, low-cost and so on. The fieldbus technical emergence solved traditional field control system's defects that be not overcomed by traditional field control system himself, and implemented distribute industry control, monitor system which is high performance and dependability. Currently, the fieldbus technique has been extended and used in the industry field with rapid speed that is not in the past. The rapid development of fieldbus not only provides a good chance to develop the flight data acquisition system, bus also challenges the low-leveled technology of flight data measurement.The LonWorks technique, one of influential the fieldbus techniques, is open, interaction operation control network .It has high reliability, security, interaction operation, easy realization, being flexible network and so on. LonWorks technique has been used widely in the kind of field. The abroad had already started launching an extensive research in the application in the aviation field to the LonWorks technique; however the LonWorks technique still is placed in a beginning stage in the domestic.In this paper, according to bus technique agreement of the LonWorks, combining request of measurement and control of air-borne, designed and implemented air-borne intelligent distributed controlling network data acquisition system based on LonWorks.It mainly apply for flight parameter, industrial control and intelligent building etc. This system is modular design and master-slave construction, which combines one administration of network node and four slave nodes. Network management node is in charge of the network operation control, the configuration of the four slave nodes, the storing of collected data and the generation of PCM signal and the transmission of system time control signals. Network management node adopts PC/104 embedded computer as the main controller, besides, in order to support LonWorks network platform, it adopts Windows 98 as the operating system. The four slave nodes collect the signals of dc voltage, thermal resistance, strain and frequency counters in flight test respectively. These nodes are communicated with LON-bus. The communication medium of LON-bus is twisted-pair cable and the communication rate is 1.25Mbps.Of these four slave nodes, neuron chip FT3150 and microcontroller C8051F064 are the core. And the full-duplex communication is implemented by the means of NeuroWire between them. In the digital quantity node, the measurements of frequency, enumeration, and period are done by CPLD, which has very high measurement accuracy. Besides, the system adopts the standard R.S232 interface, which is helpful for the extending of system functions.Experimental results show the system satisfies the request of the speed of air-borne data acquisition and the request of synchronization of nodes, and satisfied basically designing requirement.